Hung Vu-Khac1, Thuy Nguyen Thi Thanh2,
Giang Nguyen Thi Thu1, Chi Hieu Leand Van Duy Nguyen3,4*

1Institute of Veterinary Research and Development of Central Vietnam, Nha Trang, Vietnam.
2Research Institute for Aquaculture No. 3, Nha Trang, Vietnam.
3Faculty of Engineering and Science, University of Greenwich, Chatham, Kent, UK.
4Institute of Biotechnology and Environment, Nha Trang University, Nha Trang, Vietnam.

Abstract

Microsporidia, which are ubiquitous obligate intracellular parasites responsible for a variety of diseases and economic losses in farming, have different transmission strategies. While horizontal transmission relies on sufûcient parasite numbers released into environment, vertical transmission requires host reproduction to occur leading to a lower virulence, and also induces a sex ratio distortion. The second strategy has been reported in a broad range of hosts from protists to mammals, in which insects and amphipod crustaceans as the most common. The present study shows the first evidence of vertical transmission of a microsporidia in decapod crustaceans via an experimental description of the infection by Enterocytozoon hepatopenaei (EHP) in whiteleg shrimp Penaeus vannamei. The group of healthy shrimp was infected with EHP by feeding with infected-shrimp tissue and sharing habitat. The presence of EHP in the infected shrimps was detected by using Polymerase Chain Reaction (PCR) method with specific primers EHP-510F/EHP-510R and histopathological analysis. The Nauplius, Zoae 1 and Zoae 2 stages collected from the infected female broodstocks demonstrated that EHP can infect offspring from their parental shrimp, and interestingly EHP can be detected from Nauplius stage of shrimp by the use of PCR method.

Keywords: aquaculture, diagnosis, Enterocytozoon hepatopenaei (EHP),
PCR (Polymerase Chain Reaction), pathogenesis, shrimp.